The radar system, which is being developed by aerospace firm
Lockheed Martin for the United States Air Force, has successfully
detected orbiting
space junk, company officials announced March 8. The Air
Force also approved Lockheed's preliminary design for the system
on Feb. 29, they added.

The Air Force is looking to replace the aging Air Force Space
Surveillance System (AFSSS), which it has used since 1961 to
track satellites and pieces of space junk — called "resident
space objects" in industry jargon.

"The successful detection and tracking of resident space objects
are important steps in demonstrating technology maturity, cost
certainty and low program risk," Steve Bruce, vice president of
the Space Fence program for Lockheed Martin, said in a statement.
"Our final system design incorporates a scalable, solid-state
S-band radar, with a higher wavelength frequency capable of
detecting much smaller objects than the Air Force’s current
system." [ Worst
Space Debris Events of All Time ]

Lockheed is developing its Space Fence under an 18-month, $107
million contract awarded last year. The company hopes to win
another Air Force contract to actually build its system; the Air
Force plans to award that production contract later this year.

Space junk — stuff like old rocket bodies, defunct satellites and
the pieces spawned when these objects collide — is a growing
problem in Earth orbit. NASA estimates that our planet's debris
cloud contains about 22,000 pieces as large as a softball and
500,000 bigger than a marble. The number of pieces at least 1
millimeter wide likely runs into the hundreds of millions.

All of this fast-moving junk poses a threat to the 1,000 or so
operational satellites currently zipping around our planet, as
well as the International
Space Station and other crew-carrying craft.

Many researchers think the amount of space junk around our planet
has reached a critical threshold. There's now so much of the
stuff that collisions will generate a continual, ever-escalating
cascade, causing the debris cloud to keep growing even if
humanity launched no new spacecraft.

One such collision occurred in 2009, when the
Iridium 33 communications satellite slammed into a
defunct Russian satellite. The cosmic smashup spawned more than
2,000 new large debris fragments, and many more too small to be
tracked and catalogued.

Lockheed's Space Fence is designed to help deal with this
problem. The system, which will ultimately consist of S-band,
ground-based radars at two or three different different
geographic sites, will detect, track and catalog more than
200,000 orbiting objects, company officials have said. The first
Space Fence site could be up and running by 2017.